Traditionally, many chemical processes, particularly the production of fine chemicals and pharmaceuticals require a three stage operation which includes the steps of:
1. reacting the starting materials and crystalising the resulting product, PA1 2. filtering the product, and PA1 3. drying it. PA1 1. a requirement to disconnect and reconnect the service pipes for the different operations as a result of rotating the apparatus, PA1 2. the provision of two drive systems, a large one for rotating the apparatus and another for controlling a double-shafted agitator system comprising a stationary agitator for reaction and an axially operable smoothing arm for the filtration process, and PA1 3. a space requirement for rotation of the apparatus and the provision of extra safety features as a result of the apparatus's rotation
This process requires at least two vessels, a reaction vessel and a filtration drying unit. Both the reaction vessel and the filtration drying unit utilize drive shafts to operate agitators and smoothing arms respectively. The drives are both expensive and bulky as are the vessels. Furthermore, the reaction vessel is ideally set up above and to the side of the filtration unit so that the reactant can be easily transferred from the reaction vessel to the filtration drying unit. This arrangement takes up space (both height and width) which could be utilized in other ways.
Also from the processing stand point the transfer of material at the end of each stage gives rise to a risk of contamination and reduced yields.
An improved vessel has been supplied by Rosenmund AG under the Trade Mark NUTREX. This multi-purpose apparatus offers the capability of carrying out the operations of reaction, filtration and drying in immediate sequence within a single vessel.
One end of the vessel acts as a reaction/crystallization unit whilst the other end acts as a filtration/washing/reslurry unit, it being necessary to rotate the single vessel through 180.degree. from a position in which reaction takes place to a position in which filtration takes place. The apparatus can then be rotated through a further 50.degree. (230.degree. in total) to a position in which drying and discharge can take place.
Whilst such an arrangement saves space, there being a single unit compared to the at least two separate units of conventional apparatus the arrangement suffers a number of draw backs. These include:
It is an object of the invention to provide an improved multi-purpose apparatus without the problems associated with the aforementioned prior art.